Jet propulsion boat

ABSTRACT

A jet propulsion boat includes a boat body, a handle bar, an engine, a jet propulsion mechanism, a reverse gate, and a shift operating device. The handle bar is attached to the boat body. The handle bar extends in a width direction of the boat body. The engine is housed in the boat body. The jet propulsion mechanism is configured to generate a propulsion power from a drive power of the engine. The reverse gate is located rearward of the jet propulsion mechanism. The reverse gate is configured to move so as to change a direction of a jet flow from the jet propulsion mechanism. The shift operating device is rotatably attached to the handle bar about a shaft center parallel or substantially parallel to a center line of the handle bar. The shift operating device is configured to rotate so as to switch a position of the reverse gate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a jet propulsion boat.

2. Description of the Related Art

Japanese Laid-Open Patent Publication No. 2006-240446 discloses a jet propulsion boat including a reverse gate that moves so that the direction of a jet flow from a jet propulsion mechanism is changed, and a shift operating device to switch the position of the reverse gate. The shift operating device is arranged below a handle bar and is mechanically coupled to the reverse gate through a link mechanism.

SUMMARY OF THE INVENTION

However, if the operation of the reverse gate by the shift operating device is motorized, the shift operating device can be arranged for easier operation because the freedom of where to position the shift operating device improves.

Preferred embodiments of the present invention provide a jet propulsion boat that improves the operability of the shift operating device.

A jet propulsion boat according to a preferred embodiment of the present invention includes a boat body, a handle bar, an engine, a jet propulsion mechanism, a reverse gate, and a shift operating device. The handle bar is attached to the boat body. The handle bar extends in a width direction of the boat body. The engine is housed in the boat body. The jet propulsion mechanism is configured to generate a propulsion power from a drive power of the engine. The reverse gate is located rearward of the jet propulsion mechanism. The reverse gate is configured to move so as to change a direction of a jet flow from the jet propulsion mechanism. The shift operating device is rotatably attached to the handle bar about a shaft center parallel or substantially parallel to the center line of the handle bar. The shift operating device is configured to rotate so as to switch a position of the reverse gate.

According to preferred embodiments of the jet propulsion boat disclosed herein, the operability of the shift operating device is improved.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the main configuration of a jet propulsion boat according to a preferred embodiment of the present invention.

FIG. 2 is a schematic view of a configuration of a steering handle according to a preferred embodiment of the present invention.

FIGS. 3A, 3B, and 3C are side views of portions of the jet propulsion mechanism.

FIG. 4 is a block diagram of a control system according to a preferred embodiment of the present invention.

FIG. 5 is an internal configuration of a boat body according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following describes a schematic configuration of a jet propulsion boat 100 with reference to the drawings. FIG. 1 is a cross-sectional view of a schematic configuration of a jet propulsion boat.

The jet propulsion boat 100 is preferably a so-called personal watercraft (PWC), for example. The jet propulsion boat 100 includes a boat body 2, an engine 3, a fuel tank 4, a jet propulsion mechanism 5, a reverse gate 6, a seat 7, and a steering handle 8.

The boat body 2 includes a deck 2 a and a hull 2 b. The seat 7 is attached to the deck 2 a. The seat 7 is arranged above the engine 3. The steering handle 8 for steering the boat body 2 is arranged in front of the seat 7. The configuration of the steering handle 8 is described below. A pump case 2 d is provided in the hull 2 b. The pump case 2 d is arranged over and beside the jet propulsion mechanism 5 and the reverse gate 6.

An engine room 2 c is provided inside the boat body 2. The engine room 2 c houses the engine 3 and the fuel tank 4. The engine 3 includes a crankshaft 31. The crankshaft 31 is arranged so as to extend in the front-back direction.

The jet propulsion mechanism 5 generates propulsion power to propel the boat body 2 with a drive power from the engine 3. The jet propulsion mechanism 5 sucks in and sprays water around the boat body 2. The jet propulsion mechanism 5 preferably includes an impeller shaft 50, an impeller 51, an impeller housing 52, a nozzle 53, and a deflector 54.

The impeller shaft 50 is arranged to extend rearward from the engine room 2 c. The front portion of the impeller shaft 50 is coupled to the crankshaft 31 through a coupling device 36. The rear portion of the impeller shaft 50 is inserted into the inside of the impeller housing 52 through a water suction device 2 e of the boat body 2. The impeller housing 52 is coupled to a rear portion of the water suction device 2 e.

The nozzle 53 is arranged rearward of the impeller housing 52. The impeller 51 is attached toward a rear portion of the impeller shaft 50. The impeller 51 is arranged inside of the impeller housing 52. The impeller 51 rotates with the impeller shaft 50 to suck in water from the water suction device 2 e. The impeller 51 sprays the sucked in water rearward from the nozzle 53.

The deflector 54 is arranged rearward of the nozzle 53. The deflector 54 includes a jet orifice 54 to spray a jet flow from the jet propulsion mechanism rearward. The deflector 54 is configured to divert the spray direction of the water from the nozzle 53 to the left or to the right in response to an operation of the steering handle 8. The deflector 54 is arranged to swing in the up and down directions. The deflector 54 is configured to divert the spray direction of the water from the nozzle 53 along the vertical direction in response to an operation of a trim up switch 84 a and a trim down switch 84 b described below.

The reverse gate 6 is arranged rearward of the jet propulsion mechanism 5. The reverse gate 6 is arranged to move so that the spray direction of the jet flow from the jet propulsion mechanism 5 is changed. Specifically, the reverse gate 6 is arranged to be moved to a forward movement position (see FIG. 3A) that allows the jet flow from the jet propulsion mechanism 5 to flow rearward, a reverse movement position (see FIG. 3B) that allows the jet flow from the jet propulsion mechanism 5 to flow forward, and a neutral position (see FIG. 3C) that allows the jet flow from the jet propulsion mechanism 5 to flow so as to keep the boat body 2 from moving. The drive system of the reverse gate 6 is described below.

FIG. 2 is a schematic view seen from the rear of the steering handle 8.

The steering handle 8 includes a handle bar 81, a grip 82, a shift operating device 83, and a switch arrangement device 84.

The handle bar 81 is attached to the boat body 2. The handle bar 81 is arranged so as to extend in the width direction (i.e., left-right direction) of the boat body 2. In the present preferred embodiment, a center line 81S of the handle bar 81 is parallel or substantially parallel to the width direction. However, the center line 81S of the handle bar 81 may be angled with respect to the width direction.

The grip 82 preferably is a handle for an operator to grasp. The grip 82 is attached to the outer end of the handle bar 81. The grip 82 is arranged to the outer side of the shift operating device 83. In the present preferred embodiment, the grip 82 is fixed to the handle bar 81 such that the grip 82 does not pivot with respect to the handle bar 81.

The shift operating device 83 is preferably an annular member that the operator operates to switch a position of the reverse gate 6. The shift operating device 83 is arranged to the inner side of the grip 82. The shift operating device 83 preferably is attached so as to encircle the handle bar 81.

The shift operating device 83 is arranged to rotate about a shaft center 83S that is parallel or substantially parallel to the center line 81S of the handle bar 81. The shaft center 83S of the shift operating device 83 is preferably congruent with the center line 81S of the handle bar 81.

The shift operating device 83 is arranged to move to a forward movement shift position corresponding to the forward movement position of the reverse gate 6, a reverse movement shift position corresponding to the reverse movement position of the reverse gate 6, and a neutral shift position corresponding to the neutral position of the reverse gate 6. In the present preferred embodiment, the forward movement shift position is a position rotated a certain amount (e.g., about 30 degrees) from the neutral shift position in a first direction D1 about the shaft center 83S. The reverse movement shift position is a position rotated a certain amount (e.g., about 30 degrees) from the neutral shift position in a second direction D2 that is opposite the first direction D1. The neutral shift position is between the forward movement shift position and the reverse movement shift position. A shift operating signal that indicates an operation of the shift operating device 83 is input into a reverse gate control unit 200 (see FIG. 4) discussed below. The shift operating signal includes a “forward movement signal” that indicates that the shift operating device 83 is positioned in the forward movement shift position, a “reverse movement signal” that indicates that the shift operating device 83 is positioned in the reverse movement shift position, and a “neutral signal” that indicates that the shift operating device 83 is positioned in the neutral shift position.

A biasing member 83 a is embedded inside the shift operating device 83. The biasing member 83 a biases the shift operating device 83 back to the neutral shift position when the shift operating device 83 is positioned in the forward movement shift position or the reverse movement shift position. As a result, the shift operating device 83 returns to the neutral shift position due to the energizing force of the biasing member 83 a when the operator pivots the shift operating device 83 from the neutral shift position in the first direction D1 or the second direction D2. Therefore, the shift operating device 83 returns to the neutral position when the operator removes their hand from the shift operating device 83 in the forward movement shift position or the reverse movement shift position.

The switch arrangement device 84 is attached to the handle bar 81 to the inner side of the shift operating device 83. The switch arrangement device 84 is provided with the trim up switch 84 a, the trim down switch 84 b, and an engine cutoff switch 84 c. The trim up switch 84 a is a switch to raise a trim position of the deflector 54. The trim down switch 84 b is a switch to lower the trim position of the deflector 54. The engine cutoff switch 84 c is a switch to stop the engine 3.

Next, a drive system of the reverse gate 6 will be described with reference to the drawings. FIGS. 3A to 3C are side views of a configuration of the reverse gate 6. FIG. 4 is a block diagram of a control system of the jet propulsion boat 100.

As shown in FIGS. 3A to 3C, the jet propulsion boat 100 includes a reverse gate drive mechanism 11. The reverse gate drive mechanism 11 preferably includes a first link mechanism 12 shown in FIG. 3, and a first electric motor 210 shown in FIG. 4.

The reverse gate 6 is attached to the nozzle 53 through the first link mechanism 12. The reverse gate 6 is driven by the first electric motor 210 to move to the forward movement position, the reverse movement position, and the neutral position. FIG. 3A illustrates a state in which the reverse gate 6 is in the forward movement position. FIG. 3B illustrates a state in which the reverse gate 6 is in the reverse movement position. FIG. 3C illustrates a state in which the reverse gate 6 is in the neutral position.

As shown in FIG. 3A, the reverse gate 6 in the forward movement position moves away from a position facing the jet orifice 54 a. The reverse gate 6 in the forward movement position allows the jet flow from the jet propulsion mechanism 5 to flow rearward without changing the direction of the jet flow. Therefore, the reverse gate 6 in the forward movement position allows the boat body 2 to move forward.

As shown in FIG. 3B, the reverse gate 6 in the reverse movement position faces the jet orifice 54 a. The reverse gate 6 in the reverse movement position changes the direction of the jet flow from the jet propulsion mechanism 5 to flow forward. Therefore, the reverse gate 6 in the reverse movement position allows the boat body 2 to move backward.

As shown in FIG. 3C, the reverse gate 6 in the neutral position faces the jet orifice 54 a. The reverse gate 6 in the neutral position changes the direction of the jet flow from the jet propulsion mechanism 5 to flow to the left and right of the boat body 2. Specifically, the discharge amount of the jet flow in the left and right directions from the reverse gate 6 is increased by opening wide a pair of left and right openings 55 a provided on either side of the reverse gate 6. As a result, the boat body 2 holds a stable position without moving forward or backward.

As shown in FIG. 4, the first electric motor 210 that drives the reverse gate 6 is controlled by the reverse gate control unit 200. The reverse gate control unit 200 is programmed to control the first electric motor 210 in response to the shift operating signal output from the shift operating device 83.

Specifically, the reverse gate control unit 200 causes the reverse gate 6 to be moved from the neutral position to the forward movement position when the forward movement signal is output after the neutral signal is output from the shift operating device 83. Next, the reverse gate control unit 200 holds the reverse gate 6 in the forward movement position without returning to the neutral position even if the neutral signal is output from the shift operating device 83. The reverse gate control unit 200 then causes the reverse gate 6 to move from the forward movement position to the neutral position when a reverse movement signal is output from the shift operating device 83.

Conversely, the reverse gate control unit 200 causes the reverse gate 6 to move from the neutral position to the reverse movement position when the reverse movement signal is output after the neutral signal is output from the shift operating device 83. Next, the reverse gate control unit 200 returns the reverse gate 6 to the neutral position from the reverse movement position when the neutral signal is output from the shift operating device 83.

The following describes an arrangement of the reverse gate control unit 200 and the first electric motor 210 with reference to the drawings. FIG. 5 is an internal configuration diagram of the boat body 2 illustrating an arrangement of the reverse gate control unit 200 and the first electric motor 210.

As shown in FIG. 5, the reverse gate control unit 200 and the first electric motor 210 are accommodated inside a housing case 300. The case 300 is preferably attached to a side surface of the pump case 2 d provided in the rear end portion of the hull 2 b. The case 300 is preferably made of a material having a high coefficient of thermal conductivity (e.g., aluminum and the like).

The pump case 2 d encompasses the jet propulsion mechanism 5 and the reverse gate 6 (not shown in FIG. 5, see FIG. 1). The inside of the pump case 2 d is filled with water. Therefore, heat generated by the reverse gate control unit 200 and the first electric motor 210 is transmitted to the water through the housing case 300 and the pump case 2 d. As a result, the reverse gate control unit 200 and first electric motor 210 are able to effectively discharge heat.

The shift operating device 83 is rotatably attached to the handle bar 81 about a shaft center 83S that is parallel or substantially parallel to the center line 81S of the handle bar 81. Therefore, the operator is able to easily switch the position of the reverse gate 6 by gripping and rotating the shift operating device 83 with their hand. As a result, operability of the shift operating device 83 can be improved without hindering the operability of the handle bar 81.

The shaft center 83S of the shift operating device 83 is preferably congruent with the center line 81S of the handle bar 81. Therefore, the operability of both the handle bar 81 and the shift operating device 83 are compatible in comparison to when the shaft center 83S is different from the center line 81S.

The shift operating device 83 is arranged to the inner side of the grip 82. Therefore, the operability of the shift operating device 83 is further improved since the operator can operate the shift operating device 83 by moving their hand gripping the handle bar 81 to the inner side.

The biasing member 83 a is embedded inside the shift operating device 83. The biasing member 83 a biases the shift operating device 83 back to the neutral shift position when the shift operating device 83 is positioned in the forward movement shift position or the reverse movement shift position. Therefore, the operating amount of the shift operating device 83 can be reduced when subsequently switching the reverse gate 6 to the reverse movement position since the shift operating device 83 is held in the neutral position even during forward movement.

The reverse gate control unit 200 is programmed to control the reverse gate drive mechanism 11 to hold the reverse gate 6 in the forward movement position even when the neutral signal is output after the forward movement signal is output from the shift operating device 83. Therefore, the boat body 2 is able to continuously move forward when the shift operating device 83 returns to the neutral shift position from the forward movement shift position due to the biasing member 83 a. As a result, the operability of the shift operating device 83 is further improved since there is no need for the operator to hold the shift operating device 83 in the forward movement shift position while the boat body 2 is moving forward.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above preferred embodiments and various modifications may be made within the scope of the present invention.

Although the reverse gate 6 in the neutral position is described in the above preferred embodiments as preferably changing the direction of the jet flow from the jet propulsion mechanism 5 to flow to the left and right of the boat body 2 as shown in FIG. 3C, the present invention is not limited as such. The jet flow from the jet propulsion mechanism 5 may flow in other directions so that the boat body 2 does not move forward or backward when the reverse gate 6 is positioned in the neutral position. For example, the reverse gate 6 in the neutral position may cause the jet flow from the jet propulsion mechanism 5 to flow half toward the front and half toward the rear.

Although the shaft center 83S of the shift operating device 83 is described in the above preferred embodiments as preferably being congruent with the center line 81S of the handle bar 81, the present invention is not limited as such. The shaft center 83S of the shift operating device 83 may not be congruent with the center line 81S of the handle bar 81. For example, the shift operating device 83 may be arranged adjacent to and/or above the grip 82.

Although not mentioned in particular in the above preferred embodiments, the shift operating device 83 may include a resisting member that limits or prevents rotation of the shift operating device 83 when the speed of the boat body 2 is high. This type of resisting member may be activated when the boat body 2 equals or exceeds a certain speed or when the engine 3 equals or exceeds a certain number of rotations, and may have a mechanism to provide a resistance force to the rotation of the shift operating device 83. The resisting member may be completely fixed to the shift operating device 83, and may be a member that restrains the ease of movement of the shift operating device 83. Consequently, a warning may be provided to the operator so that a phenomenon such as bow diving and the like does not occur.

The jet propulsion boat 100 may be another type of jet propulsion boat without being limited to a personal watercraft. For example, the jet propulsion boat may be a jet boat.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims. 

What is claimed is:
 1. A jet propulsion boat comprising: a boat body; a handle bar attached to the boat body, the handle bar extending in a width direction of the boat body; an engine housed in the boat body; a jet propulsion mechanism configured to generate a propulsion power from a drive power of the engine; a reverse gate located rearward of the jet propulsion mechanism, the reverse gate configured to move so as to change a direction of a jet flow from the jet propulsion mechanism; and a shift operating device rotatably attached to the handle bar about a shaft center parallel or substantially parallel to a center line of the handle bar, the shift operating device being configured to rotate so as to switch a position of the reverse gate.
 2. The jet propulsion boat according to claim 1, wherein the shaft center of the shift operating device is congruent with the center line of the handle bar.
 3. The jet propulsion boat according to claim 1, wherein the handle bar includes a grip arranged at an end portion thereof in the width direction of the boat body, and the shift operating device is arranged toward an inner side of the boat body relative to the grip.
 4. The jet propulsion boat according to claim 1, wherein the reverse gate is configured to move to a forward movement position that directs a jet flow from the jet propulsion mechanism rearward, a reverse movement position that directs the jet flow from the jet propulsion mechanism forward, and a neutral position that directs the jet flow from the jet propulsion mechanism so as to keep the boat body from moving in a front-back direction; and the shift operating device is configured to rotate to a forward movement shift position corresponding to the forward movement position of the reverse gate, a reverse movement shift position corresponding to the reverse movement position of the reverse gate, and a neutral shift position corresponding to the neutral position of the reverse gate.
 5. The jet propulsion boat according to claim 4, further comprising a biasing member that biases the shift operating device back to the neutral shift position when the shift operating device is positioned in the forward movement shift position or in the reverse movement shift position.
 6. The jet propulsion boat according to claim 5, further comprising: a reverse gate drive mechanism configured to move the reverse gate; and a reverse gate control unit programmed to control the reverse gate drive mechanism in response to an operation of the shift operating device.
 7. The jet propulsion boat according to claim 6, wherein the reverse gate control unit is programmed to control the reverse gate drive mechanism so as to keep the reverse gate in the forward movement position when the shift operating device is returned from the forward movement shift position to the neutral shift position by the biasing member.
 8. The jet propulsion boat according to claim 6, wherein the reverse gate control unit is programmed to control the reverse gate drive mechanism so as to switch the reverse gate from the reverse movement position to the neutral position when the shift operating device is returned from the reverse movement shift position to the neutral shift position by the biasing member.
 9. The jet propulsion boat according to claim 1, further comprising a resisting member configured to provide a resistance force to resist rotation of the shift operating device when a velocity of the boat body is more than a predetermined value and when a number of rotations of the engine is more than a predetermined value. 